Historically, studio-quality sound, which can best be described as the full reproduction of the complete range of audio frequencies that are utilized during the studio recording process, has only been able to be achieved, appropriately, in audio recording studios. Studio-quality sound is characterized by the level of clarity and brightness which is attained only when the upper-mid frequency ranges are effectively manipulated and reproduced. While the technical underpinnings of studio-quality sound can be fully appreciated only by experienced record producers, the average listener can easily hear the difference that studio-quality sound makes.
While various attempts have been made to reproduce studio-quality sound outside of the recording studio, those attempts have come at tremendous expense (usually resulting from advanced speaker design, costly hardware, and increased power amplification) and have achieved only mixed results. Thus, there exists a need for a process whereby studio-quality sound can be reproduced outside of the studio with consistent, high quality, results at a low cost. There exists a further need for audio devices embodying such a process, as well as computer chips embodying such a process that may be embedded within audio devices or located in a device separate from and not embedded within the audio devices and, in one embodiment, located as a stand-alone device between the audio device and its speakers. There also exists a need for the ability to produce studio-quality sound through inexpensive speakers.
In cellular telephones, little has been done to enhance and optimize the audio quality of the voice during a conversation or of audio programming during playback. Manufacturers have, in some cases, attempted to enhance the audio, but generally this is accomplished utilizing the volume control of the device. The general clarity of the voice ‘sound’ remains fixed. The voice is merely amplified and/or equalized. Moreover, the settings for amplification and/or equalization are also fixed and cannot be altered by the user.
Further, the design of audio systems for vehicles involves the consideration of many different factors. The audio system designer selects the position and number of speakers in the vehicle. The desired frequency response of each speaker must also be determined. For example, the desired frequency response of a speaker that is located on the instrument panel may be different than the desired frequency response of a speaker that is located on the lower portion of the rear door panel.
The audio system designer must also consider how equipment variations impact the audio system. For example, an audio system in a convertible may not sound as good as the same audio system in the same model vehicle that is a hard top. The audio system options for the vehicle may also vary significantly. One audio option for the vehicle may include a basic 4-speaker system with 40 watts amplification per channel while another audio option may include a 12-speaker system with 200 watts amplification per channel. The audio system designer must consider all of these configurations when designing the audio system for the vehicle. For these reasons, the design of audio systems is time consuming and costly. The audio system designers must also have a relatively extensive background in signal processing and equalization.
Furthermore, in broadcast or audio transmission applications, it would be beneficial to have a split or shared processing system whereby the audio signal is at least partially processed prior to transmission, and upon receipt of the transmitted signal, the signal is further processed to create an output signal. The output signal, in various embodiments, may be specifically tailored to the output environment, output audio device, etc. In particular, this scheme has the advantage of combining dynamic range control, noise reduction and audio enhancement into a single system, where audio processing duties are shared by the encoding and decoding sides.